The present invention relates to a vehicle body rear structure of an automobile.
For a passenger car having a monocoque body structure, in comparison with a front floor that is made low to secure an interior space, in a vehicle body rear part on the rear of a rear seat, a rear-floor is provided at a position higher than the front floor to utilize a space under the rear seat as an installation space for a fuel tank and the like. For the rear-floor, rear-floor side members are provided along both side parts thereof, and rear-floor cross members are provided between the right and left rear-floor side members.
In such a vehicle body rear structure, to improve the rigidity of the rear-floor, in some cases, two rear-floor cross members are provided so as to provide a spacing in the longitudinal direction, and a pair of right and left rear-floor cross member braces are provided therebetween (refer to JP2005-112269 and JP4-75782U). The rectangular region surrounded by these four members is suitable for disposing a part that is desired to avoid damage as much as possible, such as a base part of a fuel pipe or a brake pipe, because of its high rigidity.
However, if the rigidity of the entirety of the rear-floor is too high, the amount of deformation produced when a shock load is applied from the rear is small, so that there is a possibility that the shock energy will not be absorbed sufficiently. In the case in which the absorption of energy in this region is insufficient, the rear-floor cross members are moved frontward by the remaining shock load and come into contact with a fuel tank, and this may deform or damage the fuel tank.